23/08/2026
Cool, wet weather can turn a hidden problem into a spreading threat in your bean crop. Halo blight is a bacterial disease caused by Pseudomonas syringae pv. phaseolicola. It produces small water-soaked spots with brown centres surrounded by a distinctive pale yellow-green “halo” on bean leaves. Rain, heavy dew and prolonged leaf wetness help the bacteria multiply and move between plants through rain splash, wet foliage, contaminated seed and tools.
Protect your crop by planting clean, certified seed, avoiding seed from infected plants, using resistant or tolerant varieties where available, rotating with non-host crops, and staying out of bean fields when foliage is wet.
